maxwell



(No Model.)

W. MAXWELL.

ROTARY EXHAUST PUMP.

Patented June 7, 1887.

.Eu/eniar N. PETERS, PhntvLilhognplmr. Wumngum 0.0.

the tube E and entered the tubes 0.

UNITED STATES PATENT OFFICE.

VILLIAM MAXVELL, OF FULHAM, COUNTY OF-MIDDLESEX, ENGLAND.

ROTARY EXHAUST-PUMP.

SPECIFICATION forming part of Letters Patent No. 364,532, dated June '7, 1887.

Application filed October 8, 1886. Serial No. 215,709. (No model.) Pa ented in England December 15, 1885, No, 15,478; in France September 1886, No. 178,73I, and in Belgium September ":9, 1886, No. 74,676.

To all whom it. may concern.-

Be it known that I, WILLIAM MAXWELL, a citizen of England, residing at Glaybrook Road, Fulham, county of Middlesex, England, have invented a new and useful Rotary Exhaust- Pump, (for which I have obtained a patent.

in Great Britain,dated December 15, 1885, No. 15,478; in France, dated September 25, 1886, No. 178,731, and in Belgium, dated September 29, 1886, No. 74,676,) of which the following is a specification.

My invention relates to a construction and arrangement of rotary exhaust-pump applicable for exhausting air from vesselssuch as the bulbs of incandescentlamps--as I will describe, rcferring to the accompanying drawings. I

Figure l is a vertical section, and Fig. l is a plan, of a rotary pump according to my invention, arranged to act, in lieu of a Sprengel pump, for producing ahigh degree of vacuum. Fig. 1 is a vertical section showing a modification.

Referring first to Figs. 1 and 1, A isa basin containing mercury, and having a central. hollow boss, B, from which curved tubes 0, of small bore, extend upward and outward to an annular troughrim, D. From the center of the boss B a tube extends upward through a bearing and within a stationary tube, F, which is connected to the-lamp-bulbs or other vessels that have to be exhausted. A cup, G, is charged with mercury, which, rising in the annular space between E and F, constitutes a hydraulic joint, the height of column being made sufficient to balance the difference between the external and theinternal pressures. When the basin A and the apparatus within it are caused to revolve in the direction of the arrow, mercury, with which the basin is charged, entering the tubular part of the spindle by apertures b and passing by narrow channels the plug 1), finds its way in separate successive portions into the tubes 0, and these portions are propelled along these tubes by centrifugal force, each portion of mercury c011- stituting a fluid piston which carries away in front of it a portion of air which has descended The mercury is discharged from the tubes 0 into the trough-rim D, whence it overflows into the basin A, returning to the center to supply the tubes 0 afresh. The air carried by the mercury along the tubes 0 separates at the rim and escapes through apertures in the lid of the basin.

By inclosing the whole apparatus in achamber exhausted by an ordinary aiupump, so that the pressure acting against the outflow along the tubes 0 is considerably below that of the atmosphere, the rotary pump may be rendered effective at moderate velocity for producing a high degree of vacuum.

Obviously, instead of mercury, ametal fusible at a moderate temperature may be our ployed, the apparatus being kept sufficiently hot to maintainits fused condition.

By providing the trough D, into which the tubes 0 deliver the mercury, a store of mer cury is maintained at the mouths of the tubes, which can flow back into the tubes on a decrease of speed occurring, and thus prevent the air from entering so as to destroy the vacuum formed.

According to the modified form of pump shown in Fig. 1" the lid 0 of the basin A is stationary and has suspended from it a stationary shelf, S, along which the mercury discharged from the tubes C returns to supply the hollow of the boss B through small holes.

Having thus described the nature of my i11- vention and the best means I know of carrying the same out in practice, I claim- 1. A rotary pump for exhausting air, consisting of a revolving hollow boss or chamber from which radiate curved tubes of small diameter, and which communicates by an axial tube with the space from which the air is to be exhausted, and by apertures with a vessel containing mercury revolving therewith, the rotation of the boss with its tubes causing air, together with mercury, to be ejected from the chamber by centrifugal force through the tubes, while the ejected mercury flows by gravity back into the chamber again, substantial] y as described.

2. In a rotary pump for exhausting air, the combination of a revolving basin, A, containing mercury, the hollow boss B, with curved l subscribing witnesses, this 7th day of Septemtubes 0, extending thence to the trough-rim her, A. D. 1886.

D, and the tubes E and F with cup G charged \VM MAX\VELL, with mercury, substantially as and for the \Vitnesses: 5 purpose herein set forth. OLIVER IMRAY,

I11 testimony whereof Ihave signed my name L. V. BRINDLEY,

to this specification, in the presence of two Boih of 2S SoutlzcunptonBuildings, London, W. C. 

